[gcc r14-7037] frontend: don't ice with pragma NOVECTOR if loop has no condition [PR113267]

[Tamar Christina]

https://gcc.gnu.org/g:109f2316725bd74d85279fa749e5ea59686ad320

commit r14-7037-g109f2316725bd74d85279fa749e5ea59686ad320
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Tue Jan 9 11:19:24 2024 +0000

    frontend: don't ice with pragma NOVECTOR if loop has no condition [PR113267]
    
    In C you can have loops without a condition, the original version of the patch
    was rejecting the use of #pragma GCC novector, however during review it was
    changed to not due this with the reason that we didn't want to give a compile
    error with such cases.
    
    However because annotations seem to be only be allowed on conditions (unless
    I'm mistaken?) the attached example ICEs because there's no condition.
    
    This will have it ignore the pragma instead of ICEing.  I don't know if this is
    the best solution,  but as far as I can tell we can't attach the annotation to
    anything else.
    
    gcc/c/ChangeLog:
    
            PR c/113267
            * c-parser.cc (c_parser_for_statement): Skip the pragma is no cond.
    
    gcc/testsuite/ChangeLog:
    
            PR c/113267
            * gcc.dg/pr113267.c: New test.

Diff:
---
 gcc/c/c-parser.cc               | 2 +-
 gcc/testsuite/gcc.dg/pr113267.c | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index e7b74fb07f0..878f323dd2f 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -8445,7 +8445,7 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll,
  			   build_int_cst (integer_type_node,
 					  annot_expr_unroll_kind),
 			   build_int_cst (integer_type_node, unroll));
-	  if (novector && cond != error_mark_node)
+	  if (novector && cond && cond != error_mark_node)
 	    cond = build3 (ANNOTATE_EXPR, TREE_TYPE (cond), cond,
 			   build_int_cst (integer_type_node,
 					  annot_expr_no_vector_kind),
diff --git a/gcc/testsuite/gcc.dg/pr113267.c b/gcc/testsuite/gcc.dg/pr113267.c
new file mode 100644
index 00000000000..8b6fa08324e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr113267.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+
+void f (char *a, int i)
+{
+#pragma GCC novector
+  for (;;i++)
+    a[i] *= 2;
+}